TW201023418A - Core-shell type anode active material for lithium secondary batteries, method for preparing the same and lithium secondary batteries comprising the same - Google Patents

Abstract

Provided are a core-shell type anode active material for lithium secondary batteries including a carbonaceous material core; and a shell formed outside the carbonaceous material core, the shell including a PTC (Positive Temperature Coefficient) medium. The core-shell type anode active material for lithium secondary batteries has the shell including the PTC medium, and thus has the improved conductivity and high output density, exhibiting excellent electrical characteristics. And, a lithium secondary battery manufactured using the anode active material has excellent safety, in particular safety against overcharge and external short circuit.

Description

201023418 VI. Description of the Invention: [Technical Field] The present invention is directed to a core material for a lithium secondary battery, and a seed for preparing the core-shell type anode active material Material clock secondary battery material = and package = the core · shell type - the kind of improved electrical and safety use ^ _ ^ invention is related to the type of anode active material, 盥 a preparation \ a battery core - shell The core-shell type anode-deleting material and the prior art include

The secondary battery has a wide range of applications. -A =Electric Ιΐί and the United States, in various industrial applications, the medium and large-scale cesium clock - research and development of human batteries _ uninterrupted ☆ satellite or military radio equipment and weapon system environmental protection , such as the high crystalline carbon of graphite and artificial graphite 'or such as: i = rr ^ iable) carbon and graphitizable (inhibition of earning) carbon low knot is used as the anode activity of lithium secondary batteries material. Liufan if'ii has a low-cost, smooth discharge curve under negative voltage and initial discharge. The good two-particles are wide and have a high packing density, which is used to reduce the degree of service. And based on the phase = ink potential when molding the polar plate. Fine, female-intermediate graphite has the drawback of low reversible capacitance. Non-graphitizable carbon has the advantages of high safety and large capacitance. However, with the stone 201023418, therefore, the packing density of the non-graphitizable carbon has recently been focused on meeting the demand for safety and large capacity. The lithium titanium oxide is evaluated as one of which can be modified, and has an anode activity of a stable spar-like structure, which is used as an anode active material to cause good coffee, and voltage=charge/discharge cycle performance. Excellent, and the energy and the second == make the Junyi - because we have proposed various methods to solve the traditional anode live = the same, and 'have not found any electrical characteristics and the female fullness of the clock secondary battery are evaluated It is an excellent anode active material. / For example, Korean Patent Laid-Open Application No. 1G 2 deletes the method for preparing an anode active material, and the rate discharge characteristic of the anode active material is made by doping metal (or non-metal) in graphite. No. 669335 discloses the anode of a secondary battery in which a thermosetting resin layer is formed on the anode current collector. Metal ions present on the anode current collector diffuse into the thermosetting resin layer to produce a concentration ladder. Adding the surface of the interface of the non-fabricated interface made by the spurs, and increasing the bonding strength between them, thereby improving the life characteristics of the battery and the Korean Patent Application No. 1 0_2008-0 (H0944) An anode of a lithium secondary battery comprising an anode active material, a titanium oxide and a styrene-butadiene (SBR) rubber on the surface of the anode active material. The titanium oxide used to make carbon The surface resistance is increased to prevent the energy in the battery from being lowered. The styrene-butadiene rubber used together with titanium oxide promotes storage at high temperatures, which is due to its excellent thermal safety and bonding strength. 4 201023418 ^National Specialist 1. _ 嶋 793 uncovering - kind of anode active material, TM2 surface treatment of rate release, used to improve the high-elasticity of the clock secondary battery, etc. In order to improve the electrical characteristics of the U.S. and U.S. batteries, the safety is improved. The Japanese franchise application No. 1 () _24 secret number reveals - kind of demon = sex material, - conductive material ,—adhesive interest—PTC (positive temperature) Coefficient!> Resisting--Electric (4) Feeding, one of the secondary batteries of this type of bell: The second ingestion of the patent in the patent application disclosed in the patent privilege, the % reveals a non-water scorpion, which borrows Manufactured from a cathode-mixed layer, an anode mixed layer, and a thin layer of titanic acid and lanthanum, or by adding titanic acid and lanthanum in a non-aqueous solution, which is a modified clock secondary battery. The above-mentioned two prior art techniques have revealed that by simply mixing or adding electrodes, it is necessary to develop a clock-type secondary battery, an anode active material having excellent safety and electrical properties, and a preparation of such an - The invention relates to an anode active material, a method with excellent repeatability and high productivity. [Technical Problem] The present invention is designed to solve the above problems. The anode active material of the battery and the preparation of the seed are such a positive ==== == 赖权妓仪-Touching the yang [Technical Solution] 201023418 In order to achieve the above-mentioned objects, the nucleus material for the clock secondary battery according to the present invention contains a nucleus material and is formed on the carbon material ^ Shell outside the core, the A PTC medium is included. Leaf = The PTC medium of the invention is used in accordance with the invention, and thus has improved electrical conductivity, high output i degree' and excellent electrical characteristics and sufficient thermal safety. - ϊϊ ϊϊ, the shell may further include at least one type of metal oxide, the at least one of which is selected from the group consisting of titanium dioxide and a Japanese-type stone type titanium oxide. The core of the secondary battery of the secondary battery; ', including (S1), preparing a core for forming a carbonaceous material; and (S2), dreaming of coating with a shell forming material comprising a PTC medium The carbonaceous material forms a shell: the anode of the above-mentioned core-shell type anode active material secondary battery for a primary battery and a lithium secondary battery including the anode. [Embodiment] The anode active material for a lithium secondary battery according to the present invention will be described in detail. Before the description, we should understand that this description and the scope of the patent application in the attached patent application are limited to the meaning of the financial and the silk, and should be based on the inventors of the present invention. These meanings and concepts are consistent in terms of technical aspects. First, a core (S1) forming a carbonaceous material is prepared. The carbonaceous material used in the present invention is not limited to a specific material, and as long as the carbonaceous material can be used as an anode active material of a lithium secondary battery. The carbon g material may include a low crystalline carbon and a high crystalline carbon, as exemplified by the two. In general, ^low crucible carbon includes soft carbon and hard carbon, and the high crystalline carbon includes high temperature sintered carbon 1 such as natural graphite, Kish graphite, pyrolytic carbon, based on the phase / calendar month Rabbit fiber, medium carbon glass beads, mesophase pitch, and coke extracted from petroleum or coal tar pitch. Next, a shell 201023418 (S2) is formed outside the core by coating the core with a shell forming material containing a PTC (Positive Temperature Coefficient) medium. The pTC medium included in the shell of the anode active material according to the present invention improves the thermal safety and electrical conductivity of the battery. The PTC medium has a characteristic of "electrical constant and ferroelectricity in the vicinity of normal temperature. However, the ptc medium changes its crystal structure at a specific temperature (in the vicinity of about 12 (rc) in the case of barium titanate, and the resistance increases remarkably. Fig. 1 is an illustration of a typical PTC medium. The temperature-resistance state diagram of barium titanate in the state of particles. Figure 2(a) illustrates the cubic structure of barium titanate from a square structure lower than the phase change degree to a temperature higher than the phase transition temperature. The change diagram, FIG. 2(b) illustrates that the temperature is lower than the phase transition temperature (Ti4+, and FIG. 2(c) shows the temperature is about 12〇°c. The PTC thermistor manufactured by utilizing the characteristics of the PTC medium has a characteristic that its resistance value increases with temperature (4), and is widely used in batteries, etc. = overcurrent protection. Therefore, the PTC heat The varistor is considered to be a fuse-like short-circuit protection device. However, unlike the fuse, the pTc埶 ϋΐ ϋΐ reusable advantage 'and is a high _ device, where when the ^ situation occurs, the internal resistance increases to cut Break the circuit without mechanical contact The shaft resistance is restored to a low level under normal temperature or low temperature, and the current is small. Therefore, if the PTC medium is applied to the battery, and the battery is caused by a battery, the temperature of the battery rises. The > dish degree _ about 12 (rc, M PTC media first fine for a safety device

According to the anode active material of the present invention, including the PTC, the PTC medium on the core of the carbonaceous material for maximally improving electrical characteristics and use is not limited to a specific material, and the right material has a PTC. Features can be. Typically, the PTC medium ~ - for example - is barium titanate (BaTi〇3). In the present invention, "barium titanate 7 201023418 according to ΐ: = 平介? with: = fixed at - specific value = is not limited. If the PTC = f this hair 2 ^ take ' _ in the carbon f material coating J of the squid #

=:=== This surface of the S-active material is not defined, "to coat the de-contacting specific surface area of the anode PTC medium. Therefore, if it is taken, because the intrusion / 泠 is greater than 1 泖, the coating In terms of cloth efficiency, it is not easy to divide it into simple ==1: " part of the PTC medium is reduced, and the rest of the material is the most expensive material of the material, and the ratio of the carbon material to the ratio is "Impact material: PTC, α1 to the heart by weight, the content of the PTC PTC medium in the 丨钫 丨钫 垔 大于 大于 大于 PTC PTC PTC PTC PTC 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 When the PTC medium is in the above-mentioned dry circumference, no excess 2 PTC dielectric material is generated = the entire surface is coated, and the result of the present invention is obtained, and the anode active material according to the present invention The shell may further comprise a metal oxide in the form of a metal oxide such as titanium dioxide or a spar-like type. The type of spar-type zhongzi oxide is used as the bonding between the PTC medium and the 5-material of the 2010. I 'and can directly affect the de-agglomeration and screening of the nuclear material. And based on lithium metal, in the vicinity of 1.0 V to 1.2 V, the crystal = type of titanium oxide (that is, the material of the batch has a faster charging rate), thus forming on the surface of the anode within the above range a thin layer of ionic conductivity, and the active layer of the lithium titanium oxide lowers the surface resistance of the anode and prevents reaction with the electrolyte to further improve safety and life.

In the case of using natural graphite without an example of such a spallous type of lithium titanium oxide, the charge/discharge efficiency and the charge/discharge capacity are reversed because of the electrolysis of the edge portion of the high crystallinity And 'the present invention causes the lylite type bell titanium oxide nr to suppress the edge portion of the carbon (four) material and the electrolyte and in the low crystallinity according to the present day, the carbon is enhanced and the surface coating is The effect of suppressing the reaction with the electrolyte is different and the humidity sensitivity is enhanced, thereby improving the performance of the battery.兮Carbon 贱 贱 _ _ _ inhibition of the core = material to do non-water - solution between the reaction and 2: = = r pole structural damage. Therefore, the phenomenon of the surface of the anode active material of the anode active material according to the present invention can be reduced, and the average particle size of the shell oxide of the anode active material according to the present invention can be reduced according to the use of gold. It is from 2 〇 nm to 800 nm. The above: variation in circumference, ^f is exemplified by the reduction of the number of layers, and the content of the particles of the present invention can be reasonably selected depending on the purpose of use and the gold environment. For financial reasons, the type or preparation of the battery can be an oxide-to-weight ratio, and the carbon material and the gold are up to 100:5. Buying material: metal oxide = 100:0·55 9 201023418, it is required that the shell of the anode active material according to the present invention can be increased by inhibiting the powder resistivity caused by the material constituting the shell The conductivity of the anode active material is increased, and the discharge/charging characteristics are improved. The conductive lion according to the present invention may be used alone or in combination with an electric metal, a conductive barrier and a conductive polymer, for example, Li, obstruction = blackening, acetylene black, graphite, activated carbon. Super_p or Conductive Jen is not limited to this invention. Preferably, the guide is produced by the patient: the lung is smaller or smaller. When the average particle size is less than (4), the ratio is increased to reduce the amount of addition, or the rib is used to improve the coating effect, and the average particle size is the most ambiguous [, the value ii* is limited to - a specific value. It is about Μ"" or a larger conductive material, but it is not suspected of this. And if the average particle size is larger than 8 G () mn, it is difficult to form a shell together with other materials constituting the shell. The type of the secondary battery may be decorated according to the purpose of use or the content of the conductive material in the shell may be determined. For example, if the carbonaceous material is 100 parts by weight, it may include 0.1 part by weight of the conductive material, but the present invention is suppressed. If the conductive material is promoted, the effect of the material is not bribed. However, the maximum value of the content of the conductive material in the shell is not determined to a specific value. For example, in view of the improved conductivity and the maximum basis weight, the method of coating the carbon core from 5 parts of the wire can be used without limitation, and the typical coating process used in the first m-threak, The method can be used to select the coating process. For example, a typical coating process and a wet coating process. (4) Column I includes dry type 201023418 The wet coating process allows the coating material to be uniformly dispersed. By way of example, the wet coating process is generally carried out in a subsequent manner: a dispersion liquid or a suspension liquid in which the coating material is dispersed or a solution in which the coating material is dissolved is sprayed or impregnated into the anode active material, and then dry. However, if water is used as the solvent, the solution is applied in the wet coating process, in order to properly mix the carbonaceous material of one core with the metal oxide of a shout, a surfactant is required, and Dihydrate. For this reason, it is difficult to finish the water contained in the carbonaceous material, the reaction generated by the reaction, and the preparation of the anode active surfactant. Further, an additional drying and pulverizing process is required, and after the 。, the surface shape may become uneven, resulting in the dry coating of the powder comprising the coating material shell mechanically coated. Shear, impact or pressure is applied as required to allow for ίί coating. In particular, in the present invention, the characteristics in the shell are utilized. Therefore, in the present invention, the anode and the clock secondary battery of the clock secondary battery can be manufactured by using the active material of the above-mentioned anode active material of the present invention. In the lithium--::5, the anode of the lithium secondary battery made of the active material can be made irrespective of the square of the prior art. The following describes a method for fabricating a clock secondary battery electrical electrode active material coated with a current collector' so that the collector "(four) material H electrode active material composition includes a current collector on the poly (four) composition is directly coated In the i dry = the = active material composition is coated on the - ride into the phase, ^ separate the film from the pillar, and stack it 201023418 = the collector n. Here 'the pillar is not limited The pillar can support the electrode active material layer, and the pillar is obtained by adding Co, Νι or Μη to the above-mentioned bell-containing metal oxide such as jjNi, Γ〇π夕社. The material, the telluride or the halide, rather than the gold oxide of the material, or may be vulcanized, the binder may be polyvinylidene fluoride hexafluoropropyl ester, ethylene diene, polypropylene , polymethyl methacrylate, hydrazine, & matter, typically 'the conductive material may be carbon black or acetylene, and The bath, acetone or Ν_methylpyrrolidine __methylpyrr〇ii-^ is made into a 1: pole' and a cathode assembly is fabricated on a cathode electrode plate and an anode electrode plate. The lithium secondary battery of the present invention is completed by the ω ΐ ' ' and the electrolyte for the clock secondary battery is filled into the scorpion. The preferred embodiment of the present invention is described in detail. Embodiments. However, the description of the side shots and the specific actual tube filaments show the preferred specific examples of the present invention, but they are only given by way of illustration, so the spirit of the present invention will be described in detail from here. It is obvious that those who are familiar with this technique are obvious. Example 1 <Preparation of core-shell anode active material> Preparation of nuclear carbonaceous material, mesophase graphite powder (Mesophase Graphite powder, 'MGP' (manufactured by Sinosteel Carbon Chemical Co., Ltd.); and the material of the shell is prepared as a spar type lithium titanium oxide having a particle size distribution of 30 to 8 Å. The average particle size is prepared to be 400 nm. Barium titanate, Super-P with an average particle size of 500 nm and an average particle size of 2 〇nm Ti〇2. Secondly, make 1 gram MGp, 201023418 18 grams of spar-type lithium titanium oxide, 10 grams of titanate lock, 5 grams of Super_p

Ti〇2 are mixed with each other and in a dry coating system =

The mixture was treated in Micron Corp, 雠130), spinning == 2500 rpm (revolutions per minute), and the treatment time was 3 minutes using an anode active material. Dry w core-calling type <Manufacturing of anode and lithium secondary battery> The electrically conductive carbon of the prepared anode impurity material and the polypolaridenefluoride (PVdF) as a binder are mixed at a mixing ratio of 85=7. And, add, (N-methylPyrr〇lid〇ne) to obtain a suitable viscosity of the coating, and then compress it, and use a secondary battery to absorb 7 L·mm - lithium metal oxide The composition, the touch (4) is used as a partition between the anode and a cathode, and is applied to the 'secondary battery.' The size of the object is "5 coffee thick x6 °4 see x95 mm long, and its design capacity is 3 〇〇〇! ηΑ1ι. Example 2 An active material, an electrode and a lithium secondary battery were used in the same manner as in Example 除 except that 15 g of a sparous titanium oxide and 2 () of Example 3 were used. Flying table anodes Example 4 Except that TiQyx was not used, the same active material as in Example 2, an electrode and a lithium secondary battery. Eight Ik Anodes Example 5 A 1% polar active material, an electrode and a lithium secondary battery were fabricated in the same manner as in Example 1 except that the gas was not oxidized. Comparative Example 1 < 13 201023418 Same as "Beside" and Comparative Example 2 Comparison with Example 1 Comparative Example 3 Except that MGP was used alone as the anode active material, and was produced in the same manner as in Reference Example 1. —Electrode and Zhongji characteristics evaluation 1. Powder characteristics The anode active material prepared in Example 1 was tested with a laser = ί i average particle size DlG, D5G and D9g 'At the same time, the ultrasonic dispersion of the field, and the target of the field I Analysis System (Malvem Instruments, Mastersizer 2000E) _ Diluted average particle size. Fig. 3(a) shows the measurement results of the anode active material before coating, and the value of the average particle size before the measurement of the average particle size after coating 3(b) is: H5.569 Liu, = 1^2 _ and D9g=3G 279 (4); and the specific value of the average particle size after coating is horse, .D10=l5.525 炯, 〇5〇=21 587 焖 and D9〇=3〇._ gas. - Also, 5 strokes were performed using a 1 (10) graduated cylinder to measure the degree of vibration and the volume change before and after coating was measured. The measurement result is that the average particle size and the tap density are almost not 3^/ according to the coating content. Up to 5ί, the average particle size is reduced by 2%, and the tap density is increased.

To examine the surface characteristics of Example 1 and Comparative Example 1, the mapping of the core-shell carbide particles obtained in this 1 was measured using SEM 14 201023418 父). Example 1) σ and Example 3·Electrification (1) Specific capacity and initial efficiency 1) Manufactured according to an example and comparative example - a half-cell, with a charge/discharge cycle system, using the half-cell to measure specific capacitance and initial efficiency, and the test results Not shown in Table 1. • 2) and make a complete battery' at a temperature of 25. The battery is initially charged under a constant current-constant voltage (CC-CV) condition with a current density of _ mA h and a charging voltage of 4.2 V, and after a 10-minute rest period The 1500 mAh discharge capacitor was discharged until the voltage was 2.7 V' and the initial charge/discharge capacity, initial efficiency and specific capacitance were measured, and the results of these measurements are shown in Table 2. [Table 1] Classification coating material · Coating amount 1st cycle efficiency ratio capacitance (% by weight) (%) (mAh/g) Example 1 L, B, C, T 1.8/1.0/0.5/0.1 90.8 320.4 Example 2 L, B, C, T 1.5/2.0/0.5/0.1 90.0 314.0 Example 3 L, B, C 1.8/1.0/0.5 89.7 310.0 Lean 4 L, B, C 1.5/2.0/0.5 89.8 306.0 Example 5 B, C , T 1.0/0.5/0.1 91.0 321.0 Comparative Example 1 XX 91.5 330.0 Comparative Example 2 X 5 (B), Mixed 88.5 312.0 Comparative Example 3 X 2 (B), Add 88.0 311.0 L : Li4Ti5〇12, B: BaTi03, C : Super-P, T : Ti02

[Table 2] 15 201023418 Classification coating material First charging cycle First discharge cycle 1st cycle efficiency capacitance __ Ring (mAh) Ring (mAh) Rate (%) (rn A h/p) Example 1 L, B, C, T 3635.7 3036.4 83.5 149 8 Example 2 L, B, C, T 3660.4 3062.5 83.7 149 2 Example 3 L, B, C 3635.7 3036.5 83.5 147 8 Example 4 L, B, C j 3646.0 3030.4 83.1 147 4 Example 5 B, C, T 3614.0 2918.0 80.7 139 5 Comparative Example 1 X 3644.0 3011.5 _82.6 150.9 Comparative Example 2 5(B), Mixed 3611.0 2927.4 81.1 140 6 Comparative Example 3 2(B), add 3701.4 3047.3 82.3 145.3

As shown in Tables 1 and 2, it was found that when the amount of the coating of the lithium titanium oxide is increased, the initial charge/discharge efficiency and the specific capacity are lowered.

And by Tables 1 and 2, we found that the initial charge/discharge efficiency and specific capacitance of Examples 1 to 5 were lower than those of Comparative Example , because

The surface of the MGP is tinted with a nanometer-sized clock of titanium oxide, which makes the irreversible capacitance in different voltage ranges, so these examples! To 5 shows a relatively low ratio 1 valley 1 H This is not an important element of the battery. In contrast, Comparative Example 1 exhibited higher initial charge/discharge efficiency and specific capacitance, but it exhibited very poor characteristics in terms of conductivity and safety. (2) Discharge characteristics

The discharge characteristics and the low temperature properties when the current density is changed are measured to evaluate the improvement of the conductivity. Private 1) The discharge characteristic when the current density is changed is implemented under the condition of constant current-constant v〇ltage (CC_CV) with a current density of 3000 mAh and a charging voltage of 42 V; After 1G minutes of rest, 〇5 to 15 Q c

Discharge until the county is 2.7 V. Table 3 shows the ratio of the discharge capacity of H-silin 15 C before and after the high-speed discharge of H cloth, and the discharge capacity and current density = C (1500 mAh). Fig. 6 is a view showing a discharge impurity in a temperature change per secondary battery. 201023418. The lithium secondary battery was fabricated from the anode active material prepared according to Example 1 and Comparative Example 3. 2 Test the discharge characteristics at low temperature, with a temperature of 25 t, a range of 2.5 to 4.2 V, and a current density of 1 C. At -10 〇C, charge with a current density of 1 (: at low temperature) The test results of the discharge characteristics are shown in Table 3, and FIG. 7 is a graph illustrating the discharge characteristics of the current density change in each lithium secondary battery, wherein the lithium secondary battery utilizes an example according to an example 3 Preparation of anode active materials. [Table 3] !________ ____ Classification - — ~~ One coating material 15 C Discharge characteristics (@0.5 C, %) -~- @-10 °c Special characteristics (@25 0Γ 〇/, Example 1 ---—— — — L, B, C, Τ 86.1 --~~----- 84.2 Example 2 L, B, C, Τ 85.9 ----_ 81 ι Really 3 L, B, C 83.9 -------__ 78 g Example 4 L, B, C 82.6 ----- 77 6 Example 5 B, C, Τ 80.4 ~——~~~~~~77 < Comparison example 1 X 85.8 / / ·) ------_ « Λ Λ Comparative Example 2 5(B) ‘Binding 75.7 Comparing Example 3 2(B), adding 77.7 ′ ο · ζ 75.3 ❹ _ Drop: This improves the table of j j j material.

At the same time 'by simply mixing the carbonaceous material disk S acid yttrium, resulting in uneven surface of the electrode ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ Cyclic characteristics, due to the uneven surface of the electrode, the electric wind characteristics, especially 17 201023418 (3) overcharge characteristics, after the performance of the thermal insulation and nail puncture test are also evaluated according to examples and comparative examples to prepare the anode active material The overcharge characteristics, the characteristics of the insulation period and a nail puncture test. 1) Perform an overcharge test and perform overcharge at a current density of 3000 mAh until the voltage is 12V, 18V and 24V. Observe the shape change of the battery and the surface fox, 'y yoshi fruit is shown in Table 4. Figure 8 (Example 丨: a; Comparison Example 3: b) Diagram of the state of the overcharged battery and the change of the illuminance when the MAP is 24V. = 2β) The thermal safety of the anode active materials obtained in the examples and the comparative examples was evaluated using batteries of the same size. The batteries were fully charged until the voltage was 4.2V and remained at 15 Torr. 〇 匣 匣 ,, and observe that as time goes by = fire. The results are shown in Table 4 '_0_ Figure 9 is a graph illustrating the state of the battery and the temperature change of each of the anode active materials prepared according to Example 1 and Comparative Example 3. '3) After the nail puncture test was evaluated, the surface temperature of the battery was observed, and this was not shown in Table 4. Fig. 1 () (Example i: a; Comparative Example 3: b) & : J: The battery state and surface temperature change of each of the batteries of the anode active material gas k prepared according to Example i and Comparative Example 3 Picture. ’

—~~~Εϋ) 12V

18V A, 60 A, 82 B, 110 B, 123 B, 120 D, 295 C, 173 B, 106 A state, maximum surface temperature of the battery (° 〇 comparison example 1 - comparison with j case 2 comparison with real ^ 2 24V A, 75 B, 107 C, 175 B, 112 C, 260 XXD, 183

No change, B: smoke, C: fire, d: explosion 18 201023418 sex. Level safety comparison with fine comparison, ratio ====== As mentioned above, its electrical performance is poor. /, 'Wenwen's fullness' but core-shell type anode mm characteristics and safety 'Industrial applicability according to the present invention】 The core of the present invention is made of the core-shell type anode active material. Electrical characteristics and safety. (4) Heart Clock-Secondary and a method for preparing a core-shell type anode material having an excellent repeating battery according to the method of the present invention - [Simplified illustration] chart. The male diagram showing the resistance state of the barium titanate particles at the special temperature indicates that the cubic structure of the barium sulphate is lower than the phase transition temperature. ^崎料(目3a) 纲3b) Example 1 (®4b^ scanning electron microscope) II (SeanningEleetrGnMi_c〇pe, particle cross-section of cross-section material; d:c mapping). Mapping image, b.Tl mapping, C : Ba diagram shows the discharge of the temperature in the lithium secondary battery when the temperature is changed. The output is made by the wire according to the _ and the comparison with the electricity: when the electricity in the money pool is changed, the anode is prepared by using the example 3. ^ by using according to Example 1 with a ratio of 19 to 201023418 by making 24v ί overfill each of the borrowing active materials made by 5 Figure 8:) and comparing with Example 3 ((10)) prepared by the positive meter. Battery state and surface temperature change of the battery Fig. 9 is a diagram showing the battery state diagram of the anode battery (Fig. 9a) prepared by using the heat insulation _ according to Comparative Example 3 (Fig. %). A lithium two Figure 10 is an illustration of the yang used in the nail test and the comparative example 3 (Fig. 10b). Battery status active material / l〇a) of the secondary battery with a surface temperature change chart. The parent table of a lithium Lu

20

Claims (1)

201023418 VII. Patent application scope: 1. A core-shell type anode active material for a lithium secondary battery, comprising: a carbonaceous material core; and a shell formed outside the core of the carbonaceous material, the shell comprising A PTC (Positive Temperature Coefficient) medium. 2. The core-shell type anode active material for a lithium secondary battery according to claim 1, wherein the carbonaceous material of the core is selected from at least a group consisting of: soft carbon , hard carbon, natural graphite, condensed graphite, pyrolytic carbon, based on Phase carbon fiber, medium carbon glass beads, mesophase pitch, and coke extracted from petroleum or coal tar pitch. 3. The core-shell type anode active material for a clock secondary battery according to claim 1, wherein the PTC (Positive Temperature Coefficient) medium has an average particle size of 2 nm to. 4. The core-shell anode active material for a lithium secondary battery according to the scope of the patent application, the medium-damage material and the PTC (p〇sitiVe Temperature Coefficient 'positive temperature coefficient) medium The weight ratio is carbonaceous material: pTC (Positive Temperature Coefficient) medium = i 〇〇: 〇.i to 100:2. 5. The nucleus-shell type anode active material for a clock secondary battery according to the invention of claim 2, wherein the PTC (Positive Temperature Coefficient) medium is barium titanate. 6. If the core-shell type anode active material for a lithium secondary battery is described in the application of the patent application, the If shell step comprises at least a free titanium dioxide and a spar-like titanium titanium emulsion. The metal oxides selected by the group. 7. For example, the scope of patents 帛6 is the core-shell type of the secondary battery for the secondary battery 21 201023418 polar active material, wherein the metal oxide has an average particle size of 20 to 8 〇〇 nm. The weight ratio of the core-shell type anthraquinone composite material for the clock secondary battery to the metal oxide according to item 6 is the carbonaceous material: the metal oxide=100:0.55 to 100:5 . She is surrounded by the core of the same as described in Item 1. The shell further comprises a conductive material. Lubao is used to prepare a core/shell type anode active material for a clock secondary battery, (si) is prepared to form a nuclear carbonaceous material; and P fitlang contains - (PGSitiVe Temper_ Coefficient, 11 > 5 shell The molding material coats the core of the carbonaceous material to form a shell. The core-shell type anode of the preparation of the clock secondary battery according to Item 10, wherein the coating is dry coating in the step (S2). The core-shell type impotence 氡Lt of the touch-sensitive secondary battery according to the item 1G is in ϊίΐ (82), and the shell-forming material further comprises at least one gold group 2 ϊ ϊ ϊ oxide-based free titanium dioxide and spar The preparation of the clock secondary material of the clock secondary battery according to the first aspect of the invention, wherein in the step (s2), the shell forming material further comprises an anode of the electric material on the day of the battery. It is formed on at least one side of the anode current collector to adhere to the "! material layer", the layer includes - an anode active material, - wherein the anode active material is any one of claims 1 to 9 - 22 201023418 - item 1 % polar active material. 15. - Lithium secondary battery Which comprises a cathode, an anode and a separator between the cathode and the anode is inserted. Patent wherein the anode is an anode scoping of item 14. twenty three